Stressed to the max

i've been married for 40 years and find myself wanting out of my marriage ! The man i'm married too is a good provider and i have a beautiful home...i just don't love him ! I stayed all these years because of my two children and grandchildren. We no longer sleep together ! I have met another online and fell madly in love with him, we have so much in common and he makes me laugh . i was making plans to go to him ( he lives 300 miles from me) and yes, i met him in person) I met with him after chatting for 3 months. We saw each other for 3 years( he wanted me to be sure that i wanted out of my marriage..he wanted me to leave cause i was unhappy...not leave because of him ) Then i had a close family member with cancer that i took care of for a year...well he got lonely and ended up with another woman and i living with her ( they bought a home together) that broke my heart ! but i understood that he was lonely and tired of waiting for me. Now he says he is not happy in the relationship because he can't forget about me and wants me to go to him . I told him i would but i'm not sure about anything...i just know im miserable and all this has effected my health. All i wanted was some happiness before it is too late. ( i don't ;look my age and have a nice shape.) He is 8 years younger than me ! But i know love is all that matters ! He has been with this woman for a year and im really having my doubts that he can walk out on her even though he says he is ! Lonliness and depressed is a bad place to be !!! i saw a therapist and he said if i wanted it bad enough, i can make this work !!! WHAT DO YOU GUYS THINK ????????